The present invention relates generally to color processing systems and more specifically to a color accentuation system and a component of a color processing system.
Color processing falls into two general categories, namely light projections or displays which are known as additive color systems and pigment or printing systems which are known as subtractive color systems. Color correction systems have been developed to correct for errors in the reader or scanner of the original material, signal transmission or limitations of the display or printing process. In the printing process, the correction can be directed to ink migration and physical color discontinuity. In an image or a video display, color correction can be for errors in the processing system and/or for changing the quality or color of the picture to meet certain criteria and/or tastes.
Examples of prior art systems include U.S. Pat. Nos. 4,674,963; 5,883,984; 6,053,609; 6,057,931 and 6,097,501.
In video and television, there are continuous developments of new formats. The present color accentuation system will help improve digital cameras, TV, video, and HDTV picture quality in both large and small formats. Digital still cameras and digital video cameras would have a button or command that triggers various levels of accentuation that would improve the picture quality. For example, one might take a picture on a dull, overcast day. When the accentuation button is pressed, the image will look like it was taken on a bright day.
The present invention is directed to the concept of accentuating the ultimate color image to be more vivid, color diverse, interesting to the eye and having higher color contrast. The present invention would be compatible with almost any video or print media. This patent description translates well to the CMYK color space, which is the system generally associated with the printing industry. CMYK stands for Cyan, Magenta, Yellow, and Black. These colors are related to the primary colors, red, yellow and blue, with black being considered by this invention as the absence of color. TV's and video use the RGB (Red, Green, and Blue) color space. The color accentuation system described herein can be converted into any known or new color space or system, whether additive (light) or subtractive (ink, paint, etc.)
The primary colors are red, yellow, and blue, and combinations thereof. Rainbow colors are generally considered the vivid, bright colors and are either a primary color or two primary colors mixed at some ratio/percentage in a subtractive color space. In a subtractive primary color space or process, as the percentage of the lowest percentage third color component increases, the overall color becomes more dirty and eventually becomes shades of grays and/or browns. This directly relates to additive color processes and spaces through color space conversion.
An area in an image is a set of adjacent pixels in the image that have substantially the same color, in other words, substantially the same color component magnitudes. A practitioner of ordinary skill will recognize that the benefit of the invention can be attained by determining the accentuation function once for all the pixels in an area because the adjacent pixels have substantially the same color component magnitudes. Therefore, the invention can be applied to an image on a pixel by pixel basis (where the accentuation function is calculated and applied to each pixel individually) or on an area by area basis (where the function is calculated for an area of the image and the same function applied to each pixel in the area). The overall accentuation of the total image in this system is not color linear over the image.
The system determines the relative magnitude of each color component. The color components are the set of colors that are the axes in a given color space. In Red, Blue, Yellow, RBY (the primary color space), R, B and Y are the color components. The invention selects and adjusts the magnitude of one or more of the colors as a function of the determined relative magnitudes of each color component. The type and amount of the adjustment is a function of the relative magnitude differences. One or more of the magnitudes is adjusted to change the relative magnitudes. Typically, the difference in a subtractive color space (e.g., CMY(K)) is between the lowest and middle magnitude color. Also, typically, the lowest color component is reduced in the subtractive color space. In CMY(K), no adjustment is made if only two colors are present in the area or pixel being investigated. Black (K) is not considered a color in the initial accentuation step.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.